A flexible tube is conventionally equipped, for example, with a refrigerant-tight, corrugated metal hose that is enclosed in a flexible metal cladding resistant to pressure in a radial direction, with radial spacing provided between the corrugated hose and the metal cladding. With this configuration, the corrugated metal hose leads refrigerant to a predetermined location while maintaining airtightness. Here, when the corrugated metal hose circulates refrigerant sent, for example, from a refrigerant compressor, the corrugated metal hose alone cannot withstand pressure of the refrigerant and pressure pulsation caused by a refrigerant compressor. Consequently, the flexible metal cladding resistant to radial pressure bears pressure acting on the corrugated hose and other forces. Also, when the corrugated hose is subjected to an internal pressure load, an axial force is caused in the corrugated hose to try to grow in length, and the flexible metal cladding bears the axial force as well.
When the refrigerant pressure and pressure pulsation described above are produced, friction occurs between the corrugated metal hose and flexible metal cladding, which might lead to breakage of ridges on an outer side of the corrugated metal hose in the radial direction. Thus, a flexible tube has been proposed that absorbs the friction by installing an intermediate member such as a plastic hose between the corrugated metal hose and flexible metal cladding (see Patent Literature 1).